Having not played the game, my best guesses and reasons will be below,
Overpowered:
Big Game/Clutch - Having an entire team be on fire is just a ridiculously strong skill. The players play much better and it just really impacts the game. In fact, Big Game might be the more overpowered as starting out on fire leads to big things which would just keep the fire going. I wouldn't be surprised to see someone be able to keep 50+% of their team on fire throughout the game as it doesn't seem to go away quickly.
Coachstradamus - see the abused section
Light a Fire - This will depend on what the max version of this skill is, but my guess is its as such (Level 1: COLD -> NORMAL, COLD -> HOT, COLD -> VERY HOT). If that is the case being able to call a timeout to get all cold or below players to very hot would be a huge swing that would impact the game ala Big Game and Clutch.
Abused:
Coachstradamus - I just feel like everyone will use this to try and get the 25% guess at your opponent's next play. Will be interesting to see if this can be countered via audibleing in the same formation.
Matchup - Knowing how all your opponents players are playing (i.e. cold) will probably just lead to even more of the same play (toss sweep right against poor DEs/LBs on that side, deep bombs against poor cbs, etc).
I don't really think any of the recruiting ones would be too OP.